Dog Age Calculator

Why "multiply by 7" is wrong

The popular rule of multiplying a dog's age by 7 to get its "human age" isn't based on real biology — it was a rough marketing-era approximation. Dogs mature far faster than humans in their first two years and then age more slowly afterward, and how fast they age later in life also depends heavily on their adult size.

The AKC size-based chart this tool uses

According to the American Kennel Club's chart, a dog's first year of life is equivalent to about 15 human years for every size category. The second year adds roughly 9 more human years (24 total) for small, medium and large dogs, or about 10 more (22 total) for giant breeds. After that, each additional dog year adds a fixed number of human years depending on adult size: about 4 years for small dogs, 5 for medium, 6 for large, and 7 for giant breeds — reflecting the fact that larger breeds tend to age faster and have shorter lifespans than smaller ones.

How to use it

1. Enter your dog's current age in years.
2. Select their adult size category (based on expected adult weight, not current puppy weight).
3. Read the equivalent human age.

This is a widely used approximation rather than an exact science — individual breeds and even individual dogs vary, and a vet who knows your dog's specific breed and health history can give you a more personalized sense of their life stage.